1. Field of the Invention
The present invention relates generally to piezoelectric components and, more particularly, to a novel piezoelectric resonator maximizing the efficient use of mechanical vibration of a piezoelectric member and to a piezoelectric component, such as an oscillator, particularly a voltage controlled oscillator, a discriminator, or a filter, containing the novel piezoelectric resonator.
2. Description of the Related Art
FIG. 16 is a sectional view of an essential portion of a structure for supporting a piezoelectric resonator on a substrate in a conventional piezoelectric component 1 related to the present invention. The piezoelectric component 1 includes a piezoelectric resonator 2, which includes a single piezoelectric substrate 3, which has, for example, a flat block shape having rectangular major surfaces (obverse and reverse surfaces). The single piezoelectric substrate 3 is polarized along the direction of the thickness thereof, for example. Electrodes 4a and 4b are respectively provided on the obverse and reverse surfaces of the single piezoelectric substrate 3. When a signal is input between the electrodes 4a and 4b, an electric field is applied to the single piezoelectric substrate 3 along the direction of the thickness of the single piezoelectric substrate 3, and the single piezoelectric substrate 3 vibrates in the longitudinal direction.
The piezoelectric resonator 2 is supported on an insulating substrate 5 having a predetermined pattern electrode 6 on its surface. The piezoelectric resonator 2 has a nodal portion supported on the insulating substrate 5 by a mounting member 7 formed of an electroconductive adhesive or the like. The mounting member 7 is formed by applying an electroconductive adhesive to the reverse surface of the piezoelectric resonator 2 so as to extend from one end to the other end of the resonator 2 in the widthwise direction and at the center in the longitudinal direction. In this conventional piezoelectric component, the mounting member 7 is formed on the reverse surface of the piezoelectric substrate 3 by printing using a metal mask, for example. The piezoelectric resonator 2 and the insulating substrate 5 are bonded to each other via the mounting member 7. The electrode 4b on the reverse side of the piezoelectric resonator 2 and the pattern electrode 6 on the obverse surface of the insulating substrate 5 are thereby connected mechanically and electrically.
However, in the structure for supporting the piezoelectric resonator 2 on the insulating substrate 5 as shown in FIG. 16, the mounting member 7 becomes rounded, for example, by mechanical stress such as surface tension, so that the area of contact between the piezoelectric resonator 2 and the insulating substrate 5 is substantially reduced. As a result, the strength of bonding between the electrode 4b on the reverse surface of the piezoelectric resonator 2 and the pattern electrode 6 on the insulating substrate 5 is significantly reduced. Correspondingly, the electrical connection between the piezoelectric resonator 2 and the pattern electrode 6 is weak. Therefore, reduced reliability and possible failure of the piezoelectric component 1 results. Further, in the conventional supporting structure shown in FIG. 16, the thickness of the mounting member 7 is relatively small and consequently, the piezoelectric resonator 2 and the insulating substrate 5 are located very close to each other when the piezoelectric resonator 2 is supported on the insulating substrate 5. With such an arrangement, there is a risk of the insulating substrate 5 resonating with the vibration of the piezoelectric resonator 2 and consequently causing an unnecessary response in electrical characteristics of the piezoelectric resonator 2.